Can a 2 GPM Well Support Irrigation?

Discussion in 'Irrigation' started by Greg G, Jul 7, 2011.

  1. Greg G

    Greg G LawnSite Member
    Messages: 23

    Need some suggestions from the wise old owls here. Have a homesite on 2 acres, former farm land in the country outside Charlotte North Carolina and would like your opinions on what our options are. For now we would like to irrigate the front, sides and a small portion of the back yard, about 3/4 acre and run some drip lines to landscape shrubbery in the front and back and to three new red maples we planted in the front yard. Here's the scenario:

    At the time of the well installation the well driller ended up going down 508' and had to stop when he hit black rock. The well was delivering 2 gallons per minute at that point. Our builder was aware we wanted to install irrigation and advised we try it, that the well might be borderline OK if we supplemented it with an in-ground tank so we buried a 3500 gallon fiberglass farm tank that is connected to the roof down spouts with plans to connect to the well pump with a float valve if irrigation is installled. There will have to be a flow restrictor also so the house has water pressure when the tank is being filled by the well pump.

    Can a 2 GPM well pump work that hard and survive for long? Someone suggested I will get a lot of sand if I try to put that much demand on such a small well; eventually I will be pumping mud I guess he meant.

    Are there good options for other grass types that may not need as much irrigation as the Fescue we were considering. Suggestions?

    Thanks, Greg
  2. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,367

    A 2gpm well couldn't fill that tank if it ran all day. Constant running would net you about 20,000 gallons a week.

    You wouldn't be running any sprinklers directly from the existing pump, but rather be running them from a pump that draws from the fiberglass tank. If the water is cruddy, you have to decide whether to filter it, or to use dirty-water sprinklers, like the 'beloved' Maxipaw impact heads.
  3. DanaMac

    DanaMac LawnSite Fanatic
    Messages: 13,209

    Try this. Get an above ground sprinkler set up. Maybe a MaxiPaw on a stand. hook it to your hose, and see how well it works. And for how long. But as boots said, you would need a separate pump from the tank most likely. Doubtful you will get this to work for a 3/4 acre property.
  4. Mdirrigation

    Mdirrigation LawnSite Gold Member
    Messages: 3,694

    How much was the well? Do you want to do it twice ?
  5. Greg G

    Greg G LawnSite Member
    Messages: 23

    Additional info:

    We're looking at having a Toro system installed. The plan is to install another pump to pump water for irrigation from the in-ground tank. We would compute water demand and stagger zone timing as necessary. As you mentioned it would take time to refill the tank and this would have to be taken into account when drawing up the zone plan. Also a float valve will be installed in the tank to maintain it at 2/3 to 3/4 which will leave room for additional filling from rain when available.

    We did talk about the possibility of drilling again to see if we can get a better well if this one is not enough but the builder advised trying what we have first as there are no guarantees another attempt will produce a better well although it might. First well was $8800 I think.

    Thanks for the replies!!
  6. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,367

    For the money, you try running a system with a jet pump above the tank. Depending on the soil and the weather, and the extent of your plantings, feeding a 3/4 acre landscaped property, is probably more than 2 gpm will support, so there might be times you have to let the lawn go wanting, in order to keep shrubs and trees alive.

    Messages: 18,668

    NC State has a pretty good extension site for drought hardy turf and plant recommendations.
  8. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,367

    Also, Toro has little to recommend itself for dirty-water sprinkling, as opposed to the humble impact heads, so you would be heavily filtering the tank water.

    Messages: 18,668

    Seems I recall Mike has a situation like this he dealt with pretty successfully. Maybe he'll weigh in.
  10. Greg G

    Greg G LawnSite Member
    Messages: 23

    There just wasn't room in the budget for irrigation at the time the house was being finished nor much left for landscaping either which we have been doing a little at a time. We lost our battle trying to save the fescue in the front yard this year so have to possibly re-think that choice again. We have been watering by moving hoses and sprinklers around but it's an all day job and there are times it just did not get done. We have not experienced any water delivery/ pressure problems using that arrangement that I am aware of. We recently obtained a couple of estimates for irrigation and decided to give the nod to a local installer our builder originally lined up. He prefers to install Toro because he believes their local support is much better than the others. I have tried to read up on other's experience and opinions on the various brands and many here seem to prefer Rainbird and some of the Hunter stuff. I asked him about Hunter stainless steel sprinkler heads, for example and he replied they still have plastic shafts, I think he said.

    We do have a good lawn maintenance contractor who is very attentive and helpful and gives us great personal service and he suggested the well might be too small to keep up and additionally said he hates to see us put Toro in. Installer says he has been putting these tank float valve systems in for 16 years. Wife is currently very stressed at thinking of trying to drill another well. My boss was building at the same time we did about 5 miles down the road and drilled 5 wells before they got water. He was down over 700 feet with each attempt and got 50 GPM on the 5th attempt. He has $50K invested in well drilling now but then he also earns a lot higher than I do.

    I do appreciate the tip on the NC State Extension site... will check that out.

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